Although Lear begins as a figure of authority and order, when he gives up his power and Goneril and Regan turn against him, he falls apart, going mad. Moreover, his personal decline parallels a farther-reaching dissolution of order and justice in the British state. Lear's error, based on blindness and misjudgment, doesn't just ruin him personally. It leads to a political situation in which there is no order to guarantee justice, despite his (and Gloucester's) repeated appeals to the gods.
Cordelia's first answer to Lear's command that she pronounce her love for him, the answer that first enrages him against her, is (in 1.1) is "nothing." After that first appearance, the word "nothing" recurs constantly throughout the play in the mouths of multiple characters. The repetition of this word highlights the theme of nothingness, and of the complete lack of meaning that results from nothingness – after all, when everything is destroyed, it is not possible to compare anything to anything else, and in such a void, without any ability to compare, nothing can have any meaning. And, ultimately, it is hard to argue that the ending of the play offers any justice at all: while the "bad guys" of Edmund, Goneril, Regan, and Cornwall are all killed, so are the heroes of Lear, Gloucester, and Cordelia. Nearly the entire social order, good and bad, is annihilated and turned to nothing. As Lear himself cries out in the moments before he dies, while holding the dead Cordelia in his arms, with his kingdom destroyed: "Never, never, never, never, never" (5.3.372).
Disintegration, Chaos, Nothingness ThemeTracker
Disintegration, Chaos, Nothingness Quotes in King Lear
To take the basest and most poorest shape
That ever penury in contempt of man
Brought near to beast."
Nature I you stands on the very verge
Of his confine."
That bide the pelting of this pitiless storm,
How shall your houseless heads and unfed sides,
Your looped and windowed raggedness defend you
From seasons such as these? O I have taken
Too little care of this."
Had I your tongues and eyes, I'd use them so
That heaven's vault should crack. She's gone forever."